Theater sound system



Aug 31,1943- v A. LE`R. uPToN I 2,328,369 I I THEATER SOUND SYSTEM FiledJuly 51, 1942 m L v recordings.

Patented Aug. 31, 1943 UNITED STATES N PATENT f OFFICE,

` ,2,328,369 y I y "THEATEnsoUNn SYSTEM o `Albl'tlf Roy Upton, st.Louis, Mo, Aiuilication muy ai, 1942, serial No. 453,;25

2 claims. (c

This inventionrelates to'theater` sound systems conventional. soundlsystemin a motion picture theatei-incliniesl apparatus* in a`projection booth where` aorec'ording-v incident toal motion picture isrun tominitiate signals. These signals are ampliedmin equipment usuallyin the booth, from which anfelectric circuit to `a.

` loud speaker, or horns,1 omastage at the rear of ja `screen.` `Thepresentlinvention has as its object; the provision vof convenienti andsatisfacf tory means whereby theqloud speakerdmaype used to serveas aVreproducer for other than such The pickup,v `for.` the second source maybe a microphone, phonograph, or radio rey ,c eiver. A furtherk objectofthe invention is yto provide remote control means whereby the inputand disconnected at a `single place. Another object is to provide ameans whereby the source through the originalV path 3 and 4.

grue switch iz is adouble throw switch so that it` `may be closed not`only on the terminalsfor `the` lines 9 and II), but also "on theterminals for the leads` Il and I8 whichlead from thecontrolpanel,.wherebyJ the circuit selected at the control panelis connectedto'the stagespeaker l'.

A doublethrow switch `I9` onthe control'panel has its blades connectedwith the leads. I'I `and I8 .,(and `when the switchIZ is properly set,`are fromgeither ofthetwc sources may be connected of the input in a`systemof the ,character described may be changed with avoidance ofvoltage surges and noise.

These objects, and the construction and operation of the system will beapparent from the `following detailed description, taken in connec- `beunderstood how the present invention is used to modify theconventionalsystem. y

Leads 9 and I0 are connected to lines I and 2 l respectively, and leadto switches II and I2. 'Ihe switch II may connect the lines. I and 2through thelrfleads Sand Illwith lines I3 and I4 to a control panel. Theswitch I2 may connect the lines I and 2 through the leads 9 and I0 toleads I5 `and I6, which are connected to the lines 5 and 6 respectively,thus providing a direct path l comparable vto the line sections 3 and 4.

It willlbe understood by closing the switch II` on the terminals for thelines Si` and I0, that the circuit I, 2 from the projection booth iscondescrlbedjconnectlons may be made with the circuit `Ii. 6" leading tothe loud speaker on the nected to the control panel, and here as later'`connected `to` the speaker l) `and is" adapted to connect these leadswith the lines I3y and I4,lo1 with the lines 2| and 22. The latterpairof lines areconnected in a manner hereinafter described, with a bridgingamplifier 23 receiving its input signal from a source other than theprojection booth, such as a phonograph, microphone, `or radio receiver.scribed in my copending application filed on even date herewith may beused as such source.

A ballastresistor 24 may be placed across the lines I3 and I4 by oneblade of a switch 25. For convenience the switch has a doubleblade,

one blade connectingthe resistor 24 as described, l

while the other blade connects an A. C. supply circuit 26with anindicating 'lamp 21.

The line 2| branches; one branch being connected `with a switch `29, theother branch being connected to a ballast resistor 30. The resistor 30is connectedby a line 3l to the output of the amplier 23. The switch 29is arranged to connect with a branch 32 of the line 3|, to by-pass theresistor 30, or with a branch 33 of the line 22, which is connected tothe output of the amf` pliiler opposite the line 3 I When the switch 29is connected to the branch horns by the switch I2, but when that switchis` closed on the terminals of the lines I'I and Iii, and the switch IIis closed, the system is connected for operation by remote controlthrough f the switch I9 on the control panel. If remote The systemillustrated and de- Y control is not desired, the switch II is open andthe switch I2 is closed on the lines 9 and Ii). If, however, it isdesired to operate the system at the remote control panel (whichincludes the switches I9, 25 and 29) the switch II will be closed andthe switch I2 will be closed on the terminals for the lines I1 and I8.

Then if it is desired to connect the speaker 'I (that is through thelines 5 and E) with the amplifier 23, the switches on the control.'`panels will be operated in thefollowing sequence: The switch 25 will beclosed, the switch I 9 will be closed on the terminals for the lines ZIand 22', and the switch 29 will be closed on the terminals for thebranch 32. Thereupon the path' from the amplier 23 will he through theline,v 31e, .they branch 32, switch 29, line '2I, switch Ilead I'l,.switch I2, line I5, to line 5; while the path from the opposite side ofthe amplier will bethrcugh.

line 22, switch IS, line I8, switch I2, line I6, to line 6.

When itis desired; to change the connection on the control'panel'rromthe amplierj i'to`- the lines I' and 2, the swtcheson the control panelare changedin the-reverse order. The switch-29 is connected.with` thebranch 33; then' the switch Slis reversed to connect-the'leadsJ I 'and'Alil; and the switch 25 is'c'penedi Therebyt'he-lines and 2' areconnected't'o the leads 9 land' I9; switch I I,

leads I'and llt, switchl, leads I'I'and I8, switch d l2, leads I5 andI,t'crlirie'sand-r 6L. Y A' constantA impedance attenuator 34'; may Aneused to control'the" input to the amplifierv 231;

It will'be understood thattheswitches II and 2 are intended to be'operated only when the amplifier connected through them is' dead: Inoperation, however, whenthe switches 25; mand il@ are operated in theorder specified; the resistors 24 and 3B completely protect theampliers, and the switches may be operated both without danger of damageto the amplifiers, and withoutany noiseY in the speaker.

It will be obvious that various changes may be made in the details ofconstruction, within the scope of the appended claims, Without departingfrom the spirit of this invention. Parts of the invention may be usedwithout the whole, and improvements and additions may loe made theretowhile retaining ther essence of-'theinvention I claim:

1. In a sound system a pail` of circuits each fed by an audio amplifier,a loud speaker and a circuit' thereto, a double throw switch adaptedtolconne'cteither amplier circuit with the speaker circuit, a ballastresistor, and a selector switch for selectively connecting said resistorin one of the amplifier circuits and to by pass said resistor, `a linebeing connected to the selector switchv and arranged to; lov-pass saiddouble throw switch when the resistor is connectedin said: amplifiercircuit bythe selector switch'. y

2'.- In asound'sys-temapair of'circuitseach'fed by an audio amplier, a'-loudspeaker anda cir-- cuit thereto, a double thro-w switch adaptedl tcconnecteither amplifica circuitwith the speaker circuit,aballast'resstor, a switchvf'brfconnecting and disconnecting saidresistor acrcssf'one ainplier circuit, a=secondiballast resistor, andaselector-switch for selectively con-nectihg'said secondresistor inv-theother of the yajrnpli'dercircuits andt'o by-passsaid'second resistor,aline being connected-1 tothe selector yswitch andi arranged toby-passsaiddoublethrow-switchwhen the seeond' resistor is connected* inysaid amplifierV circuit bythe selectorl switch.- l Y ALBERT LEROY UP'ION

